This adds another level of clumping on child hairs. When enabled, child hairs chose a secondary clumping target using a Voronoi pattern. This adds visual detail on a smaller scale, which is useful particularly when the number of parents is relatively small. Natural fibres behave in a similar way when they become sticky and intertwined. Hairs close to each other form a first twisted strand, then combine into larger strands. Similar features can be found in ropes: http://en.wikipedia.org/wiki/Hair_twists http://en.wikipedia.org/wiki/Rope Conflicts: source/blender/blenloader/intern/versioning_270.c